Method and apparatus for presetting knives



Dec. 26, 1967 R. CRABTREE METHOD AND APPARATUS FOR PRESETTING KNIVES Filed Dec.

United States Patent 3,359,834 METHOD AND APPARATUS FOR PRESETTING KNIVES Kenneth R. Crabtree, Portland, 0reg., assignor to Everett F. Armstrong, Siletz, Oreg. Filed Dec. 28, 1965, Ser. No. 516,850 8 Claims. (Cl. 76-101) ABSTRACT OF THE DISCLOSURE Apparatus for presetting knives including a knife support, and edge-positioning means for positioning the cutting edge of a knife supported on said support. Babbitt assemblies are formed on the back edge of the knife, and while supported against such edge positioning means, with molding devices which are assembled on the back edge. With the babbitt deposits formed, excesses are trimmed off along a line which substantially parallels and has a predetermined spacing relative to a datum line defined by the edge-positioning means.

The present invention relates to presetting knives, and more particularly to a method and apparatus for presetting knives to adapt them for placement in a knife mounting. A particular example of a knife advantageously preset as contemplated herein is the knife employed in veneer lathes to peel veneer from a log.

The usual veneer lathe has one, more often multiple knives set end to end for cutting veneer, and a cooperating roller bar which bears on the surface of a log directly adjacent where the veneer is cut. The log is mounted on spindles which have centers laterally spaced from the roller bar. To obtain satisfactory cutting, it is extremely important that the cutting edges of the knives have a certain predetermined spacing relative to a horizontal plane passed through the spindle centers, and also that the cutting edges of adjacent knives be exactly aligned. With regard to edge alignment, a tolerance of .001 inch or so is desirable in order to avoid scoring of the veneer as the same is cut.

In the past, positioning of a knife in order properly to space the cutting edge relative to the spindle centers has been accomplished by shifting the knife on an adjustable knife mounting in the lathe, and making repeated measurements to determine when proper spacing has been achieved. Such a procedure is time consuming, and therefore expensive. Additionally, it is hard if not impossible to carry out such a procedure accurately with multiple knives whereby these knives are positioned with their cutting edges in exact alignment.

A general object of the present invention, therefore, is to provide a novel method for presetting a knife, whereby a knife may easily be set up in a veneer lathe or other machine, with its cutting edge in proper position, without requiring complicated adjusting procedures in the lathe.

Another object is to provide a novel method whereby multiple knives may be preset so that their cutting edges become accurately aligned when the knives are set end to end in a lathe.

According to the invention, the desired width in a knife body is first determined from measurements made in the particular lathe intended to receive the knife body. A knife body to be used in the lathe is then built up from a knife, using deposits secured to the knife at regions distributed along the back edge of the knife. Such deposits may be molded, from babbitt or other low melting point metal, or from plastic. The knife body so formed has an overall width somewhat greater than the width desired for the knife body when it is finally mounted in place. Portions of the molded deposits are then cut or ground ofl. along a line which is spaced from the cutting edge of 3,359,834 Patented Dec. 26, 1967 the knife a distance corresponding to the previously determined desired Width for the knife body. Multiple knives may be preset with their cutting edges exactly aligned and deposits prepared at spaced points along the knives, and the deposits then cut off along a line to produce knife bodies, each having an overall width which is the same, and which equals the desired width which has been predetermined. With a knife body prepared in this manner, the same can be placed in a veneer lathe with the base of the deposits resting directly on a mounting base or shelf provided in the knife mounting, and with the width of the knife body being exactly that which results in the cutting edge being in proper position.

Each time a knife has its edge ground for sharpening, the width of the knife decreases somewhat. According to this invention, this decrease in knife width is taken care of by preparing larger deposits on the back edge of the knife. This invention further contemplates apparatus for molding deposits and then cutting them off, with edgepositioning means defining a set position for the edge of a knife each time a deposit is molded, and means defining a path for a router or other cutter spaced a set distance from such edge-positioning means. A knife is not moved from the time its edge is placed against such edge-positioning means prior to preparing deposits, until after such deposits have been molded and out 01f. Thus the overall width of a knife body prepared by the apparatus always exactly corresponds to the lateral spacing between the edge-positioning means and the path of the router, and this overall width can be exactly duplicated each time a knife is sharpened and returned to the apparatus for the preparation of new deposits.

Another object, therefore, is to provide a method of the type outlined where a knife may readily be preset on repeated occasions as the cutting edge of the knife wears.

A further object is to provide apparatus which will reliably accomplish the above objects, and which is simple to construct and easy to use.

These and other objects and advantages attained by the invention will become more fully apparent as the description which follows is read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a somewhat simplified drawing showing an end elevation of a veneer lathe, with portions broken away to illustrate a knife mounted in the lathe;

FIG. 2 is a plan view ofapparatus for presetting a knife as contemplated by the invention;

FIG. 3 is an elevation of the apparatus illustrated in FIG. 2;

FIG. 4 is a plan view, on a larger scale than FIGS. 2 and 3, of apparatus for molding a deposit of babbitt on a knife;

FIG. 5 is a cross-sectional view, taken generally along the line 55 in FIG. 4; and

' FIG. 6 is an elevation viewing the left end of the molding apparatus in FIG. 4.

Turning now to the drawings, and with reference first to FIG. 1, shown generally at 10 is a veneer lathe of the type used in peeling sheets of veneer from a log, such as the log indicated in dashed outline at 12. The log is supported on suitable spindles (not illustrated) in the lathe. The lathe includes a frame 16 and a head 18 suitably mounted on the frame. Frame 16 supports a knife 14 in an operative position where it peels veneer from log 12 on the log being rotated by rotation of the spindles. Head 18 carries a roller bar 20 which rolls on the surface of the log directly adjacent the region where the veneer is peeled from the log. The knife is clamped in place while resting on a knife mounting in the frame by clamping mechanism generally indicated at 22. Such knife mounting comprises an elongated bar 24 resting on jack screws which are distributed along the length of the knife beneath the knife, one of these screws being shown at 26. With screws 26 retracted downwardly in frame 16, the knife may be mounted with bar 24 resting directly on base 27 in the lathe. Clamping mechanism similar to mechanism 22 is fully described in US. Patent No. 3,006,392, issued on Oct. 31, 1961, entitled Knife Holder for Lathes, and reference is herein made to that patent.

Formed on the back edge of knife 14 for the purpose of presetting the knife as will be explained are deposits, such as babbitt deposit 28. These deposits support the knife by resting on bar 24 in the knife mounting. The deposits together with the knife form a knife body having an overall width, which, with the knife body mounted on shelf 24, positions the cutting edge of the knife at the exact position desired relative to roller bar 20.

Referring now to FIGS. 2 and 3, apparatus for presetting a knife as contemplated herein is indicated generally at 30. This apparatus comprises a support table 32 on :which is suitably mounted an elongated platform 34. Secured on top of this platform at locations distributed along its length are knife support bases 36, in the form of plates extending transversely of platform 34, which support a knife during presetting. These support bases together with platform 34 comprise what is referred to herein as knife-supporting means. This knife-supporting means is adapted to support several knives disposed end to end, two of such knives being indicated at 38, 40. As seen in FIGS. 2. and 3, knives 38, 40* are placed on the supporting means with their cutting edges 38a, 40a facing to the right, and with their back edges 38b, 40b facing to the left.

To one side of the knife-supporting means, the ap paratus includes means for positioning and aligning the cutting edges of knives which are supported on the knifesupporting means. Specifically, this edge-positioning means comprises a plurality of adjustable nut and bolt assemblies 42. These assemblies are distributed along the length of an elongated I-beam 44 which substantially parallels platform 34. The I-beam is mounted on table 32 by bolts such as bolts 46 shown in FIG. 3. Referring to FIG. 3, each of the nut and bolt assemblies includes a positioning bolt 48 which is screwed into web 44a of the I-beam, and a tightening nut 50* which is screwed onto the bolt. The bolt includes a head 48a which faces toward the knife-supporting means, and which forms an abutment for the positioning thereagainst of the cutting edge of a knife. As should be readily apparent, in each of the nut and bolt assemblies, the bolt is adjustable to shift the bolt head toward or away from the knife-supporting means. The assemblies define a datum line in the apparatus.

According to the invention, the presetting apparatus also includes means for clamping a knife immobile onto the knife-supporting means. Such clamping means comprises, in the embodiment illustrated, toggle clamps 52. Each clamp includes mounting plate 54 through which the clamp is bolted onto the beam 44. With reference to FIG. 3, which illustrates a side view of one of the clamps, each clamp further includes a clamping pad 56 which is suitably fastened on a clamping arm 58, and a handle 60 which is actuable to move the clamping arm whereby the pad may be brought down upon (or released from) the upper face of a knife supported on the knife-supporting means.

The presetting apparatus further comprises means for cutting off babbitt deposits which are formed on the back edge of a knife. The cutting means includes a router blade 62 fastened on a shaft 640 of an electric motor 64. The motor is operable on being energized to rotate the router blade. A carriage 66 mounts the motor, and this carriage rides on elongated rails 68, 70 which are suitably fastened to the top of table 32. These rails substantially parallel the platform along the side of the platform opposite the side which is adjacent the I-beam. With motor 64 operating, as carriage 66 is shifted along the rails, the router blade produces cutting or grinding along a plane or in what is referred to as a predetermined trimming path, which is laterally spaced a predetermined distance from the edge-positioning means and the datum line thereby defined. With reference to FIG. 3, it can be seen that router blade 62 is positioned with its rotational axis somewhat above the upper surfaces of knife-supporting bases 36.

Carriage 66 has shoes 65 (see FIG. 3) that snugly engage opposite sloping sides of rail and thus rail 70 defines the path along which the carriage moves. The lateral spacing of rail 70 from the edge of the knife as positioned by edge-positioning means 42 may be adjusted by adjustment of blocks such as block 69 which are distributed along the length of rail 70 and are fastened to the rail while positioned under table 32. Each block is adjustable toward and away from the plane of the edgepositioning means by adjustment of nuts 71 which are screwed onto a threaded stud 69a joined to the block, such nuts residing on either side of a beam 73 having suitable bores formed therein receiving the studs of the various blocks.

In preparing a knife for mounting, deposits such as those shown at 71 in FIG. 2 are prepared along the back edge of the knife. Molding devices are employed in making these deposits which may be disassembled after the molding operation to leave deposits exposed for cutting with the router. One of such molding devices is i1lustrated in FIGS. 4 through 6 and given the reference numeral 73.

Referring now to FIGS. 4 through 6, a knife as exemplified by knife 3-8, portions of which are shown in these figures, is prepared for the attachment of a deposit to the back edge thereof by cutting recesses such as those shown at 38c inwardly on the knife from the back edge. A pair of such recesses are provided for each babbitt deposit and the recesses of this pair converge on each other viewing a plan view of the knife as thus shown in FIG. 4. With the knife mounted in place, the knife is positioned on platform 34 with paired recesses as described positioned over a support base 36.

Each support base has a pair of spaced apart keyways such as those shown at 74, 76 formed therein which extend longitudinally of the base and transversely of the knife with such mounted in place.

Molding device 73 comprises a pair of keys 78, 80 which fit within keyways 74, 76 and which have one set of their ends abutting the back edge of the knife with the molding device in operative position as shown in FIGS. 4 and 5. Also part of the molding device is a cover shown generally at 81 including a riser plate 82 which rests on the top face of the knife and has a lower surface substantially in the plane of the top face, and a back piece 83. The back piece fits between the keys which are lodged in keyways 74, 76.

Referring particularly to FIG. 5, back piece 83 includes a lip 84 which extends under the support base with which the molding device is assembled. Above lip 84 is a shoulder portion 85 which abuts against the end of this support base. Above shoulder portion 85 is a ledge portion 86 substantially in the plane of the top of the support base (and thus the lower face of the knife) which ledge portion joins with a horizontal rear wall 88. With the device in operative position, the under surface of riser plate 82 shown at 8212, rear wall 88 and ledge portion 86 together with the top face of support base 36 define the top, rear extremity and bottom of a chamber located to the rear of the rear edge of the knife. Keys 78, 80 define opposed sides of this chamber. The chamber so formed functions as a mold cavity into which babbitt material is poured.

It will be noted, and referring to FIGS. 4 and 5, that the riser plate has a dimple 89 recessed into the top face thereof and extending between the base of this dimple and the chamber just described is a port 90. In pouring babbitt while in a molten state the same is directed into the dimple and such travels into the chamber through this port.

Considering now how a knife is preset for installation in a veneer lathe according to the invention, measurements are first made in the knife mounting in the lathe to determine the required width in a knife body which will produce proper spacing between the knife-cutting edge and the level of the lathe spindle centers with the knife body seated in the mounting. Once this width is determined, each of the nut and bolt assemblies 42 in the presetting apparatus is adjusted so that the heads of the positioning bolts lie in a common plane which is spaced from the path taken by the router blade when carriage 66 is moved along rail 70 a distance equal to this width. The bolts are then locked in position by tightening their respective fastening nuts.

Next, a knife which is to be preset, and which has previouslybeen provided with pairs of recesses spaced along its back edge as earlier described, is placed on top of the knife-supporting means with each pair of recesses overlying one of the knife support bases, and with the cutting edge of the knife abutting the heads of the positioning bolts which are disposed in front of the cutting edge. The knife is then clamped down on the knife-supporting means and held immobile by the toggle clamps which have their clamping pads disposed above the upper face of the knife.

With the knife thus held immobile, a molding device is seated in operative position on each of the knife support bases. Molten babbitt or other alloy may then be poured through the port in the riser plate of each molding device in sufficient quantity to fill the chamber previously described adjacent the back edge of the knife and also the recesses in the knife which communicate with this chamber. The babbitt is allowed to harden thus to form solid deposits or masses of babbitt spaced along the back edge of the knife. When the babbitt has fully solidified, the molding devices including the riser plates and keys are removed.

On removal of the various molding devices, babbitt deposits are formed which naturally have the outline of the chambers formed within the molding devices. As best seen in FIG. 5, ledge portion 86 projects rearwardly a slight distance from the adjacent edge of a support base, and rear wall 88 is also spaced rearwardly a slight distance from this support base edge. As a consequence, a babbitt deposit is formed by each molding device which, at least along a rear portion thereof, is suspended by the knife and fully exposed both along an expanse disposed opposite the knife edge (i.e., the surface bounded by wall 88 of the cover) and along margins joining with this expanse substantially in the planes of the knife faces (i.e., the surface portions defined by ledge 86 and the under surface 82b of the riser plate).

With the knife still held immobile, motor 64 is then turned on to operate the router blade, and the router blade is moved in a path by moving carriage 66 along rails 68, 70, thereby to cut off portions of each of the babbitt deposits along the mentioned cutting plane. As previously mentioned, the router blade is elevated somewhat above the top surface of knife support bases 36, such elevation being chosen to insure that in each babbitt deposit the blade will cut the entire expanse of babbitt which faces the blade. This cutting results in a knife body having an overall width, measured from the back surfaces of the babbitt deposits to the cutting edge, which is exactly that required to produce the proper spacing between the cutting edge and level of the spindle centers in the lathe when the knife body is mounted in the lathe.

According to this invention multiple knives may be preset simultaneously to obtain knife bodies all having 'the overall width desired which, when mounted in a lathe, will present cutting edges in substantially exact alignment. With the heads of the positioning bolts lying in a common plane, it makes relatively little difference whether one, two or a multiple number of knives are being set up for mounting in a lathe, since in all cases the knife edges, prior to having deposits formed, are placed in exact alignment and cutting of the rear portions of the babbitt deposit produces a predetermined overall width.

Thus, the invention provides a simple and reliable method and means for presetting one or more knives. The difiiculties encountered in adjusting knives in their mountings are avoided by first determining the desired width for a knife body in a particular mounting, and then presetting a knife outside of the mounting to have this desired width.

A knife on becoming dull must be resharpened and this, of course, decreases the overall width thereof. With the method and using the apparatus contemplated, a resharpened knife may be readily prepared into a knife body having the proper predetermined width by returning it to the apparatus as previously set up, with its edge against the positioning bolts described. The old babbitt deposits are knocked off and new ones prepared along the back edge of the knife as above discussed. Since the edgepositioning means, i.e., the positioning bolts, and rail 70 defining the path of the carriage have the same relative position that they previously had, when these new deposits are cut off along rear portions thereof, a knife body is formed having an overall width which is exactly the same as the width of the knife body prepared prior to the sharpening operation.

The apparatus, of course, is adaptable to various sizes of knives for use in different types and sizes of lathes, and knives for other applications, such as chippers, slicers, etc. To prepare the apparatus, for instance, for the preparation of a knife body which is narrower than one previ ously prepared, all that is necessary is to change the relative spacing of the positioning bolts relative to the path of the router.

It is not necessary to include bar 24 in the mounting for the knife body in a lathe, and the jack screws shown at 26 may even be eliminated with the result that the knife body rests directly on base 27 when mounted in operative position in a lathe. If base 27 is truly flat and exactly horizontal along the length thereof, rail 70 in the apparatus herein disclosed, which rail defines the path of movement for carriage 66 and the router, is positioned so as to extend along a straight line paralleling the plane defined by the heads of the various nut and bolt assemblies 42. It is usual for frame 16 to be supported on some sort of tracks to permit its advancement toward the centers of the lathe spindles as veneer is cut from the log, and it is not uncommon for the frame to be movable along the tracks with base 27 not exactly horizontal, but instead with one end of the base slightly lower than the opposite end. In this type of situation, for a knife body to have a cutting edge which has the same spacing relative to a horizontal plane passed through the centers of the spindle at both ends of the knife, requires that the knife body be somewhat wider at one end than the other. To prepare a knife body of this description, the position of rail 70 is adjusted so that it extends not exactly parallel but at a slight incline relative to the plane defined by the heads of assemblies 42. Still further, if base 27 should not be exactly flat but instead have a slight wave therein extending from one of its ends to its opposite end, this wave can also be duplicated in rail 70 by suitable adjustment. In any event, regardless of how the rail is initially set up with respect to the nut and bolt assemblies 42, once the apparatus has been set up and using the method of the invention, successive knife bodies may be prepared which have the exact overall widths desired.

It is recognized that modifications may be made either in the steps outlined or in the means described herein for the invention without departing from its basic principles, and it is desired to cover all such modifications which would be apparent to one skilled in the art and which are within the scope of the appended'claims.

It is claimed and desired to secure by Letters Patent:

1. A method of presetting plural knives for installation in a knife mounting comprising placing the knives end-toend with their cutting edges aligned, preparing at least one deposit on the back edge of each knife, and cutting off a portion of such deposits along a line which is spaced a predetermined distance from the aligned cutting edges of the knives.

2. A method of presetting a knife for installation in a knife mounting comprising preparing a deposit on the back edge of the knife by molding it on the knife, with such deposit including a mass extending rearwardly from said back edge which is suspended by the knife and is fully exposed along an expanse disposed opposite said back edge and includes margins substantially in the planes of the knife faces joining with such expanse, without moving the knife after the preparing of such deposit cutting off a portion of such deposit along a plane spaced rearwardly from the back edge of the knife, such portion being part of said mass which extends rearwardly of the knife edge, and is suspended by said knife.

3. A method of presetting a knife for installation in a knife mounting comprising: holding the knife immobile with its cutting edge extending along a predetermined datum line; providing a defined trimming path for a cutter extending along and spaced rearwardly of the back edge of the knife, with such trimming path substantially paralleling such datum line; preparing a deposit on the back edge of the knife which, with such cutting edge extending along said datum line, projects rearwardly from the knife back edge and into said trimming path; and moving said cutter along said path and into such deposit where it extends into said path, with such cutting edge extending along said datum line, to remove portions of said deposit projecting into said path along a line which substantially parallels said datum line.

4. The method of claim 1, wherein the cutting is done along a line spaced a predetermined distance from the cutting edge of the knife which distance is determined with relation to the knife mounting.

5. The method of claim 1, wherein aligning of the cutting edges is accomplished by placing the edges against preset aligned abutments.

6. For presetting a knife having a cutting edge and a back edge disposed opposite its cutting edge, apparatus comprising knife-supporting means for supporting a knife with such immobile, edge-positioning means for positioning the cutting edge of a knife supported by said knife-supporting means,

molding means adapted to seat on said knife-supporting means for molding a deposit on the back edge of a knife supported by said knife-supporting means, and

cutting means disposed adjacent said knife-supporting means operable to cut off a molded deposit along a line spaced a predetermined distance from said edgepo-sitioning means.

7. The apparatus of claim 6, wherein said molding means comprises plural molding devices for molding plural deposits on the back edge of a knife.

8. The apparatus of claim '7, wherein each molding device has surfaces which, with the device in operative position on a knife, define a cavity disposed rearwardly of the back edge of the knife, said surfaces including opposed surfaces substantially in the planes of the opposed faces of the knife.

References Cited UNITED STATES PATENTS 1,025,735 5/1912 Bosredon 76-101 1,258,891 3/1918 Goreham.

2,396,730 3/1946 Whitfield et al. 29529 2,476,151 7/1949 Le Jeune 29529 3,004,336 10/1961 Timuska 29529 X GRANVILLE Y. CUSTER, JR., Primmy Examiner. 

2. A METHOD OF PRESETTING A KNIFE FOR INSTALLATION IN A KNIFE MOUNTING COMPRISING PREPARING A DEPOSIT ON THE BACK EDGE OF THE KNIFE BY MOLDING IT ON THE KNIFE, WITH SUCH DEPOSIT INCLUDING A MASS EXTENDING REARWARLDY FROM SAID BACK EDGE WHICH IS SUSPENDED BY THE KNIFE AND IS FULLY EXPOSED ALONG AN EXPANSE DISPOSED OPPOSITE SAID BACK EDGE AND INCLUDES MARGINS SUBSTANTIALLY IN THE PLANES OF THE KNIFE FACES JOINING WITH SUCH EXPANSE, WITHOUT MOVING THE KNIFE AFTER THE PREPARING OF SUCH DEPOSIT CUTTING OFF A PORTION OF SUCH DEPOSIT ALONG A PLANE SPACED REARWARDLY FROM THE BACK EDGE OF THE KNIFE, SUCH PORTION BEING PART OF SAID MASS WHICH EXTENDS REARWARDLY OF THE KNIFE EDGE AND IS SUSPENDED BY SAID KNIFE. 